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Slender-billed Gull Larus genei

Justification
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: #http://www.aerc.eu/DOCS/Bird_taxa_of _the_WP15.xls#.
Cramp, S.; Perrins, C. M. 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.

Distribution and population
The Slender-billed Gull breeds widely at isolated, scattered localities, from Senegal, Mauritania, and the south and east of the Iberian Peninsula, through the Mediterranean, Black Sea, Asian Minor and the Middle East to east Kazakhstan, Afghanistan, Pakistan and north-west India. It winters in much of the Mediterranean, Black Sea and Caspian Sea including coastlines around the Arabian Peninsula, south to the Horn of Africa (del Hoyo et al 1996).

Trend justification
The overall trend is increasing, although some populations may be stable (Wetlands International 2006).

Ecology
Behaviour Populations breeding in central Asia are fully migratory, although other populations are sedentary or only disperse short distances (del Hoyo et al 1996, Snow and Perrins 1998). Migratory populations return to breeding colonies in late-February, most using a route along the west coast of the Black Sea (Olsen and Larsson 2003), leaving breeding sites again in July (Olsen and Larsson 2003). Many immatures also remain in winter quarters throughout the breeding season (Olsen and Larsson 2003). The species breeds from late-March to May in dense monospecific or mixed-species colonies (e.g. with terns) in numbers ranging from ten to many thousands of pairs (del Hoyo et al 1996), and is gregarious throughout the year, commonly occurring in flocks of up to 200 individuals, occasionally up to 3,000 (Snow and Perrins 1998). Habitat Breeding The species breeds on the coasts of land-locked seas (Richards 1990, Snow and Perrins 1998), on sand-spits, beaches (del Hoyo et al 1996) and islands with mudflats and marshes in shallow tidal waters (Richards 1990, Snow and Perrins 1998), and on saline inland seas and steppe lakes (Olsen and Larsson 2003). It may also frequent meadows and moist grassland by tidal inlets (Snow and Perrins 1998), and brackish or freshwater lagoons or marshes near river deltas during this season (Richards 1990, del Hoyo et al 1996, Snow and Perrins 1998). Non-breeding The species is almost entirely coastal outside of the breeding season, frequenting shallow inshore waters and salt-pans, although it generally avoids harbours (del Hoyo et al 1996). Diet The diet of the species consists mainly of fish (del Hoyo et al 1996, Snow and Perrins 1998) (c.50 % of the diet) (del Hoyo et al 1996), as well as insects and marine invertebrates (del Hoyo et al 1996) (e.g. crustaceans) (Urban et al. 1986). Breeding site The species breeds colonially with pairs nesting as close as 20-50 cm (Urban et al. 1986); large groups often splitting into subcolonies with groups centres 10-50 m apart (Urban et al. 1986). The nest is a deep scrape or shallow depression (Urban et al. 1986, Richards 1990), preferably positioned on open mud, although some pairs may nest in Salsola or Salicornia (del Hoyo et al 1996, Olsen and Larsson 2003). Management information A conservation scheme for the protection of gull and tern breeding colonies in coastal lagoons and deltas (e.g. Po Delta, Italy) involves protection from human disturbance, prevention of erosion of islet complexes, habitat maintenance and the creation of new islets for nest sites (Fasola and Canova 1996). The scheme particularly specifies that bare islets with 30-100 % cover of low vegetation (sward heights less than 20 cm) should be maintained or created as nesting sites (Fasola and Canova 1996).

Threats
Eggs and chicks of this species are preyed upon by Larus cachinnans and Larus melanocephalus (especially where colonies are frequently disturbed by humans) (del Hoyo et al 1996), and storms or cold weather may threaten breeding colonies by causing nest flooding and chick mortality (del Hoyo et al 1996). The species is threatened by pollution form oil (Cooper et al. 1984, James 1984, del Hoyo et al 1996) and plastic waste, and is exploited by local people (subsistence egg collecting) in the Mediterranean and western Africa (Cooper et al. 1984, James 1984). It also suffers from disturbance caused by local people and tourists casually visiting breeding colonies, and by habitat loss resulting from tourism development (James 1984). The species is susceptible to avian influenza, so may be threatened by future outbreaks of the virus (Melville and Shortridge 2006, Gaidet et al. 2007). Pollution from agricultural chemicals is no longer considered a likely threat (I. C. T. Nisbet in litt. 2010).

References
Cooper, J.; Williams, A. J.; Britton, P. L. 1984. Distribution, population sizes and conservation of breeding seabirds in the Afrotropical region. In: Croxall, J.P.; Evans, P.G.H.; Schreiber, R.W. (ed.), Status and conservation of the world's seabirds, pp. 403-419. International Council for Bird Preservation, Cambridge, U.K.

del Hoyo, J.; Elliott, A.; Sargatal, J. 1996. Handbook of the Birds of the World, vol. 3: Hoatzin to Auks. Lynx Edicions, Barcelona, Spain.

Delany, S.; Scott, D. 2006. Waterbird population estimates. Wetlands International, Wageningen, The Netherlands.

Fasola, M.; Canova, L. 1996. Conservation of gull and tern colony sites in north-eastern Italy, an internationally important bird area. Colonial Waterbirds 19: 59-67.

Gaidet, N.; Dodman, T.; Caron, A.; Balança, G.; Desvaux, S.; Goutard, F.; Cattoli, G.; Lamarque, F.; Hagemeijer, W.; Monicat, F. 2007. Avian Influenza Viruses in Water Birds, Africa. Emerging Infectious Diseases 13(4): 626-629.

James, P. C. 1984. The status and conservation of seabirds in the Mediterranean Sea. In: Croxall, J.P.; Evans, P.G.H.; Schreiber, R.W. (ed.), Status and conservation of the world's seabirds, pp. 371-375. International Council for Bird Preservation, Cambridge, U.K.

Melville, D. S.; Shortridge, K. F. 2006. Migratory waterbirds and avian influenza in the East Asian-Australasian Flyway with particular reference to the 2003-2004 H5N1 outbreak. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 432-438. The Stationary Office, Edinburgh, UK.

Olsen, K. M.; Larsson, H. 2004. Gulls of Europe, Asia and North America. Christopher Helm, London.

Richards, A. 1990. Seabirds of the northern hemisphere. Dragon's World Ltd, Limpsfield, U.K.

Snow, D. W.; Perrins, C. M. 1998. The Birds of the Western Palearctic vol. 1: Non-Passerines. Oxford University Press, Oxford.

Urban, E. K.; Fry, C. H.; Keith, S. 1986. The birds of Africa vol. II. Academic Press, London.

Further web sources of information
Detailed species account from Birds in Europe: population estimates trends and conservation status (BirdLife International 2004)

Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004)

Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Butchart, S., Ekstrom, J., Malpas, L., Taylor, J., Calvert, R.

Contributors
Nisbet, I.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Larus genei. Downloaded from http://www.birdlife.org on 25/12/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 25/12/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Slender-billed gull (Larus genei) 0

Key facts
Current IUCN Red List category Least Concern
Family Laridae (Gulls, Terns, Skimmers)
Species name author Brème, 1839
Population size mature individuals
Population trend Increasing
Distribution size (breeding/resident) 3,120,000 km2
Country endemic? No
Links to further information
- Additional Information on this species
- Projected distributions under climate change